High-potential insulator structure



1 Oct. 1, 1929. H. B. SMITH HIGH POTENTIAL INSULATOR STRUCTURE FiledDec. 11, 1922 iooooi 100005 INVENT'OR Ham/d B Smith ATTORNEY PatentedOct. 1, 1929 UNITED STATES PATENT erries HAROLD B. SMITH, OF WORCESTER,MASSACHUSETTS, ASSIGNO R TO WESTINGHOUSE ELECTRIC & MANUFACTURINGCOMPANY, A CORPORATION OF PENNSYLVANIA HIGH-POTENTIAL INSULATORSTRUCTURE Application filed Eecemher 11, 1822. Serial No. 606,016.

My invention relates to insulator structures and particularly tohigh-potential in sulator structures of the suspension type.

One object of my invention is to provide a suspension insulatorstructure in which a weather-protective hood having a drip portiondisposed outside the are-over zone of highest potential gradient in thedielectric field of the insulator shall, in a certain sense, constitutean element that is mechanically separate from, and independent of, theinsulator proper and that may be assembled and shipped as a portion of asupporting tower, as a part of the insulator or as a separate unit.

Another object of my invention is to provide an insulator structure inwhich the parts shall be so constructed and related as to greatlyfacilitate the handling, shipping and assembling thereof.

A further object of my invention is to pro: vide a suspension-insulatorstructure that shall be simple and durable in construction, economicalto manufacture and effective in its operation.

In my copending applications, Serial No. 548,818, filed April 1, 1922,and Serial No. 559,743, filed May 10, 1922, both entitled Insulators andassigned to the l/Vestinghouse Electric & Manufacturing Company, are setforth features which are embodied as elements in the combination of mypresent invention.

In the first of the above-mentioned applications is disclosed thefeature of so widely distributing and directing the dielectric stressesbetween the ends of an insulator as to form what may be termed a hollowfield. In other words, there is formed a dielectric field of reducedintensity at its center through which the insulator extends. Thisconstruction, as fully set forth in the application, renders the surfaceof the insulator free of damaging stresses and causes arc-over to occurat a position safely removed from the insulating surface or surfaces.

In the second of the above-mentioned applications is disclosed thefeature of so protecting the insulator of the first application as tomaterially improve the wet arc-over characteristics thereof. This isaccomplished by providing a weather-protective hood of such constructionand relation to the insulator as to provide a drip portion outside thearc-over zone in the dielectric field of the insulator. i

In the device ofthe second-mentioned application, the weather protectivehood is so constructed and related to the insulator as to constitute acomponent portion thereof. This construction adds weight and bull: tothe insulator and, as a result, may, in certain instances, presentdifficulties in handling and shipping which it is desirable to avoid.

In practicing my present invention, I provide a hood structure of theabove-mentioned type that may conveniently constitute a permanentlyassembled portion of the supporting tower or structure and that isotherwise better adapted for convenient manipulation as a separate unit.In other words, the hood may be the subject of consideration of thetower builder or of another class of operators whose duty it is to mountthe hoodsonly. Thus, the work of the operators whose duty it is to mountthe insulators will be facilitated to a high degree and an insulatorstructure obtained which is more economical and effective in every way.

Figure 1 of the accompanying drawings is a View, partially in elevationand partially in section, of a portion of a high-potential,suspension-insulator structure embodying one form of my invention, asviewed in the direction of the transmission line;

Fig. 2 is a View, similar to Fig. 1, of a modified form of my invention,and

Fig. 3 is a View, similar to Figs. 1 and 2, of a further modified formof my invention.

The structure of my invention comprises three main portions incombination, that is, a main supporting structure 1, aweather-protective device 2 and an insulator 8.

The main supporting structure 1 may be in the form of any usualstructural-steel, highpotential transmission tower or bracket having anarmor member 4 to which the other parts are immediately attached.

As illustrated in Fig. 1, the weather-protective device comprises aportion 5, preferably of inverted substantially bowl shape, but

which may be of frusto-conical or other configuration, aportion 6permanently secured to the arm at, as by rivets 7, and a portion 8 fromwhich the insulator 3 is flexibly suspended, as by a pin 9 or othersuitable means.

The insulator 3 comprises an elongated central supporting or tensionmember 10, terminal members 11 and 12 and upper and lowerelectrostatic-flux distributing members 14: and 15. The terminal member11 is secured to the portion 8, by the pin 9, and the terminal member 12is adapted to support a high-tension conductor 16. The construction,operation and characteristics of the insulator 3 and the effect thereonof the weather-protective device 2 are all fully set forth in theabovementioned co-pending applications, to which reference may be hadfor a more full and cor plete understanding of the electricalcharacteristics of the combination, as herein described. It is believedto suffice herein to point out that the specific combination, in whichthe device 2 does not constitute the top member of the insulator 3proper, has not, to the best of my knowledge, been suggested prior tothe invention of the device set forth in the above-mentioned applicationSerial No. 559,743. By not constituting the top member of the insulatorproper is meant that the device 2 does not correspond to the upperportion or unit of an ordinary insulator which is shaped like a rainshed. There are many types of the latter form of insulator but in all ofthem, to the best of my knowledge, water drops form at the lower edgesof the shed in the dielectric field of the insulator.

As shown in Fig. 1, the device 2 is adapted for assembly and shippingwith a portion of the tower 1. This renders the insulator 3 of lessweight and bulk and, consequently, greatly facilitates the mounting ofthe insulators,

ter the towers have been erected.

In the form of my invention illustrated in Fig. 2, in which similarreference Characters designate similar parts, the portion 6 of theabove-described form is modified to permit flexibility therein. This isaccomplished by dividing the portion 6 into two parts 13 and 19, theformer of which is connected to the arm 4 by the rivets 7, and thelatter of which is mounted on the portion 5. The parts 18 and 19 maypreferably be formed as eye-and-clevis members for the reception of apin 20. In this form of structure, the portions 8 and 11 may alsopreferably be formed for the reception of a screw-threaded mem ber 21,or otherwise, to have the portions 5 and 1d rigidly related.

In the form of my invention shown in Fi 3, the electrostatic stressdistributing members 14c and 15 are both of toroidal form similar to themember 15 in Figs. 1 and 2. The pin 20 is disposed at right angles tothe similar pin of Fig. 2 and the pin 9 is at right angles to the pin20. This construction provides a substantially universal flexibleconnection by which the device as a whole may move in the direction ofthe conductor 16 and the insulator may move laterally to the conductor.C o-operating stop portions 22 and 23 on the portions 8 and 11,respectively, limit the amount of lateral movement of the insulator toprevent engagement of the parts 14 and 5 and to thus, prevent too greata distortion of the field adjacent to these parts.

In all of the figures, the construction is such as to confinesubstantially all of the main electrostatic field between the members 11 and 15 and to ensure that arc-over shall never occur between themembers 15 and 5, even under wet conditions when a relatively heavyflood of water may be dripping from the lower edges of the member 5.

Also, in all of the forms, the device 2 is adapted to constitute apermanent portion of the device 1 and, in the forms shown in Figs. 2-and 3, the device 2 may be a separate unit for connection to theinsulator or to the tower previous to the final installation.

By my present invention, the devices of the above-mentioned co-pendingapplications are further developed and rendered more flexible and betteradapted to operating conditions.

lVhile I have shown and described particu-. lar forms of my invention,changes may be effected thereinwithout departing from the spirit andscope thereof, as set forth in the.

appended claims.

I claim as my invention:

1. In a high-potential insulator suspension device, the combination witha weather-protective hood structure and means for securing the latterto, and supporting the same independently of the insulator on, a mainsupporting structure, said hood structure having insulator-attachingmeans disposed adjacent to its inner upper portion, of an insulatorcomprising an insulating member, means adjacent to the upper end thereoffor detachably securing the same to said attaching means, and terminalmeans including an annular upper terminal portion disposed around thelongitudinal axis of the insulating member in definite predeterminedrelation to the hood for confining ultimate arc-over to a Zone under,and away from, the hood.

2. In a high-potential insulator suspension device, the combination witha weather-protective hood structure and means for securing the latterto, and supporting the same independently of the insulator on, a mainsupporting structure, said hood structure having insulator-attachingmeans disposed adjacent to its inner upper portion, of an insulatorcomprising an insulating member, means adjacent to the upper end thereoffor detachably securing the same to said attaching means, and terminalmeans including annular upper and lower terminal portions disposed indefinite predetermined relation to the hood around the inner upperportion, of an insulator comprising an insulating member, means adjacentto the upper end thereof for detachably securing the same to saidattaching means, and terminal means including substantially toroidalconducting surfaces in definite predeter mined relation to thehoodaround the longitudinal axis of the insulating member adjacent tothe ends thereof providing a weakened electrostatic field through whichthe insulating member extends and a field zone of maximum strengthoutside said weakened field and inside the lateral limits of the hood,the relation of parts preventing arc-over to the hood.

4. In a high-potential-insulator-suspension device, the combination witha weather-protective hood having an annular water-drip outer edge belowthe center thereof and means for securing the hood to, and supportingthe same independently of the insulator on, a main supporting structure,said hood having insulator-attaching means disposed adjacent to itsinner upper portion, of an insulator comprising an elongated insulatingstructure, means adjacent to the upper end thereof for detachablysecuring the same to said attaching means, and terminal means includingsubstantially toroidal widely radially rounded conducting surfaces indefinite predetermined relation to the hood around the longitudinal axisof the insulating structure adjacent to the ends thereof providing aweakened electrostatic field through which the insulating structureextends and a field zone of maximum strength outside said weakened fieldand inside the lateral limits of said waterdrip edge, the relation ofparts preventing arc-over to the hood.

5. In ahigh-potential-insulator-suspension device, the combination witha weather-protective hood having an annular water-drip outer edge belowthe center thereof and means for securing the hood to, and supportingthe same independently of the insulator on, a main supporting structure,said hood having insulator-attaching means disposed adjacent to itsinner upper portion, of an insulator comprising an elongated insulatingstructure, means adjacent to the upper end thereof for detachablysecuring the same to said attaching means, and terminal means, the upperof which is disposed within the hood above said water-drip edge indefinite predetermined relation to the hood, including substantiallytoroidal widely radially rounded conducting surfaces around thelongitudinal axis of the insulating structure adjacent to the endsthereof providing a weakened electrostatic field through which theinsulating structure extends and a field zone of maximum strengthoutside said weakened field and inside the lateral limits of saidwater-drip edge, the

relation of parts preventing arc-over to the hood.

6. In a high-potential-insulatorsuspension device, the combination witha weather-protective hood having an annular water-drip outer edge belowthe center thereof and means for securing the hood to, and supportingthe same independently of the insulator on, a main supporting structure,said hood having insulator-attaching means disposed adjacent to itsinner upper portion, of an insulator comprising an elongated insulatingstructure, means adjacent to the upper end thereof for detachablysecuring the same to said attaching means, and terminal'means, theupperof which is disposed within the hood above said water-drip edge indefinite predetermined relation to the hood, including substantiallytoroidal widely radially rounded conducting surfaces around thelongitudinal axis of the insulating structure adjacent to the endsthereof providing a weakened electrostatic field through which theinsulating structure extends and a field zone of maximum strengthoutside said weakened field and inside the lateral limits of saidwater-drip edge, the relation of parts preventing arc-over to the hood,said detachable securing means permitting relative movement between theinsulator and the hood and means for definitely limiting said relativemovement.

In testimony whereof, I have hereunto subscribed'my name this fourth dayof December, 1922.

HAROLD B. SMITH.

